The field of this invention is clamshell buckets and the like used for picking up and dumping a load.
Typical of the prior art known to the applicants is found in U.S. Pat. Nos. 866,628; 2,604,709; and 3,547,276. In the earlier two patents which operated with a single line, it was necessary to manually actuate the apparatus for each dumping operation and to re-set same for the next pick-up operation. A lever arm bucket using a single line system has also been used, but so far as is known, no patents issued thereon. U.S. Pat. No. 3,547,276 is believed typical of the prior commercial clamshell bucket apparatus which has a two-line system with one line system being used for raising and lowering the bucket and the other line system being used for manipulating the bucket for dumping and/or picking up a load.